//重载。
Ext.override(Ext.data.TreeStore,{
    load : function(options) {
        options = options || {};
        options.params = options.params || {};
        var me = this, node = options.node || me.tree.getRootNode();
        if(!node){
            node = me.setRootNode({
                expanded:true
            });
        }
        if(me.clearOnLoad){
            node.removeAll(false);
        }
        Ext.applyIf(options,{
           node:node 
        });
        options.params[me.nodeParam] = node ? node.getId():"root";
        if(node){
            node.set("loading",true);
        }
        return me.callParent([options]);
    }
})